Design of a Microgravity Simulation Platform for Multi-Body Dynamics Analysis in the Taiji Mission

Space gravitational wave detection through missions like China’s Taiji Program represents a critical application of drag-free satellite technology. The drag-free satellite system developed for the Taiji Mission comprises a spacecraft platform and two test masses, in which the spacecraft actively isolates the test masses from external disturbances and space environmental noise, thereby creating an ultra-stable mechanical environment for the test masses. Prior to orbital deployment, comprehensive ground testing specific to Taiji’s multi-body dynamics requirements is required to validate the system design effectiveness. Nevertheless, establishing a high-precision microgravity environment capable of evaluating satellite performance remains a significant technical challenge for terrestrial verification. The proposed microgravity simulation platform for the Taiji Mission integrates a 5-degree-of-freedom (5-DoF) motion platform with two double-stage suspended torsion pendulums. The 5-DoF platform utilizes pivot bearings to compensate for gravitational stiffness, effectively replicating the on-orbit dynamic characteristics of Taiji’s satellite platform. Concurrently, the torsion pendulums emulate both the translation motion along the sensitive axis and rotation motion about the z-axis of Taiji’s space-borne test masses. Through strategic configuration of these components, the platform achieves ground-based simulation of multi-body dynamics characteristic of the Taiji satellite. Structural parameters were designed using the Buckingham π theorem to ensure dynamic and kinematic equivalence specifically tailored for Taiji’s operational scenarios. Numerical simulations of Taiji’s typical working conditions confirm the platform’s capability to faithfully reproduce space microgravity conditions, demonstrating its effectiveness for Taiji’s pre-launch system validation.